Can bleb survival following phacoemulsification be improved by a new technique?

Abstract

Abstract: : Purpose:It is established that phacoemulsification in functioning trabeculectomies threatens bleb survival. To improve bleb survival we modified our technique. A Leweke cannula was used to maintain the anterior chamber during phacoemulsification & 5FU injected to the bleb. To assess bleb survival we did a case–control pilot study to compare our new technique with standard phacoemulsification. Methods:Patients with functional trabeculectomies who had phacoemulsification were identified. In 25 cases the Leweke cannula was used, all received 10mg of 5FU to the bleb per–operatively & 11 received post–operative 5FU. In 20 controls, HPMC was used for capsulorhexis & none had 5FU. Results:There was no major difference between groups for age, sex, past–surgery or length of follow–up (mean 23&20 months). The Leweke group had more Indian (6 vs 3) & the control group had more African / Caribbean (9 vs 2). There were more Caucasians in the Leweke group (17 vs 8). Preoperatively all but 3 cases (1 Leweke, 2 control) had pressures <21mmHg on no therapy. Post–operative failure was defined as pressure >21mmHg requiring additional medical or surgical therapy. Table 1 shows more failures in the control group(Pearson Chi2 3.28 P=0.07). 

Logistic regression was done with failure as the outcome. Crude & adjusted odds are shown in table 2.  

* Three categories used up to 1year (n=12), 1–2years (n=19) and >2 years (n=14) ⁺ Graded 0=Caucasian, 1=Indian, 2=African/Caribbean Conclusions:There is a suggestion of a protective effect in the Leweke group. Some of this may be explained by difference in ethnicity between groups. However the effect is potentially large & of clinical significance. We are planning a larger controlled trial.

Keywords: clinical (human) or epidemiologic studies: outcomes/complications • intraocular pressure • treatment outcomes of cataract surgery